Three proteins present on the surface of gametes and ookinetes have been identified by monoclonal antibodies as targets of antibodies that block infectivity of gametocytes to mosquitoes. We cloned one of these proteins by immunoaffinity purifying the protein, microsequencing tryptic peptides of the protein, and then screening genomic libraries with oligonucleotides. The methods for purifying the other target proteins for microsequencing are currently being developed. We have continued the search for novel target antigens of antibodies that block transmission of sexual stage malaria parasites, and have identified a parasite molecule that may be involved in release of gametocytes from red blood cells.